intel: Enable GL_OES_compressed_ETC1_RGB8_texture

Enable it for all hardware.

No current hardware supports ETC1, so this patch implements it by
translating the ETC1 data to RGBX data during the call to
glCompressedTexImage2D(). For details, see the doxygen for
intel_mipmap_tree::wraps_etc1.

Passes the Piglit test spec/OES_compressed_ETC1_RGB8_texture/miptree and
the ETC1 test in the GLES2 conformance suite.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Chad Versace <chad.versace@linux.intel.com>

src/mesa/drivers/dri/i965/brw_wm_surface_state.c

@@ -551,6 +551,11 @@ brw_init_surface_formats(struct brw_context *brw)
    ctx->TextureFormatSupported[MESA_FORMAT_Z32_FLOAT] = true;
    ctx->TextureFormatSupported[MESA_FORMAT_Z32_FLOAT_X24S8] = true;
    ctx->TextureFormatSupported[MESA_FORMAT_Z16] = true;
+
+   /* On hardware that lacks support for ETC1, we map ETC1 to RGBX
+    * during glCompressedTexImage2D(). See intel_mipmap_tree::wraps_etc1.
+    */
+   ctx->TextureFormatSupported[MESA_FORMAT_ETC1_RGB8] = true;
 }
 
 bool

src/mesa/drivers/dri/intel/intel_extensions.c

@@ -91,6 +91,7 @@ intelInitExtensions(struct gl_context *ctx)
    ctx->Extensions.OES_EGL_image = true;
 #endif
    ctx->Extensions.OES_draw_texture = true;
+   ctx->Extensions.OES_compressed_ETC1_RGB8_texture = true;
 
    if (intel->gen >= 6)
       ctx->Const.GLSLVersion = 130;

src/mesa/drivers/dri/intel/intel_mipmap_tree.c

@@ -38,6 +38,7 @@
 #include "main/enums.h"
 #include "main/formats.h"
 #include "main/image.h"
+#include "main/texcompress_etc.h"
 #include "main/teximage.h"
 
 #define FILE_DEBUG_FLAG DEBUG_MIPTREE
@@ -190,7 +191,15 @@ intel_miptree_create(struct intel_context *intel,
 {
    struct intel_mipmap_tree *mt;
    uint32_t tiling = I915_TILING_NONE;
-   GLenum base_format = _mesa_get_format_base_format(format);
+   GLenum base_format;
+   bool wraps_etc1 = false;
+
+   if (format == MESA_FORMAT_ETC1_RGB8) {
+      format = MESA_FORMAT_RGBX8888_REV;
+      wraps_etc1 = true;
+   }
+
+   base_format = _mesa_get_format_base_format(format);
 
    if (intel->use_texture_tiling && !_mesa_is_format_compressed(format)) {
       if (intel->gen >= 4 &&
@@ -237,6 +246,7 @@ intel_miptree_create(struct intel_context *intel,
       return NULL;
    }
 
+   mt->wraps_etc1 = wraps_etc1;
    mt->region = intel_region_alloc(intel->intelScreen,
 				   tiling,
 				   mt->cpp,
@@ -1049,6 +1059,60 @@ intel_miptree_unmap_s8(struct intel_context *intel,
    free(map->buffer);
 }
 
+static void
+intel_miptree_map_etc1(struct intel_context *intel,
+                       struct intel_mipmap_tree *mt,
+                       struct intel_miptree_map *map,
+                       unsigned int level,
+                       unsigned int slice)
+{
+   /* For justification of these invariants,
+    * see intel_mipmap_tree:wraps_etc1.
+    */
+   assert(mt->wraps_etc1);
+   assert(mt->format == MESA_FORMAT_RGBX8888_REV);
+
+   /* From the GL_OES_compressed_ETC1_RGB8_texture spec:
+    *   INVALID_OPERATION is generated by CompressedTexSubImage2D,
+    *   TexSubImage2D, or CopyTexSubImage2D if the texture image <level>
+    *   bound to <target> has internal format ETC1_RGB8_OES.
+    *
+    * This implies that intel_miptree_map_etc1() can only be called from
+    * glCompressedTexImage2D, and hence the assertions below hold.
+    */
+   assert(map->mode & GL_MAP_WRITE_BIT);
+   assert(map->mode & GL_MAP_INVALIDATE_RANGE_BIT);
+   assert(map->x == 0);
+   assert(map->y == 0);
+
+   /* Each ETC1 block contains 4x4 pixels in 8 bytes. */
+   map->stride = 2 * map->w;
+   map->buffer = map->ptr = malloc(map->stride * map->h);
+}
+
+static void
+intel_miptree_unmap_etc1(struct intel_context *intel,
+                         struct intel_mipmap_tree *mt,
+                         struct intel_miptree_map *map,
+                         unsigned int level,
+                         unsigned int slice)
+{
+   uint32_t image_x;
+   uint32_t image_y;
+   intel_miptree_get_image_offset(mt, level, 0, slice, &image_x, &image_y);
+
+   uint8_t *xbgr = intel_region_map(intel, mt->region, map->mode)
+                 + image_y * mt->region->pitch * mt->region->cpp
+                 + image_x * mt->region->cpp;
+
+   _mesa_etc1_unpack_rgba8888(xbgr, mt->region->pitch * mt->region->cpp,
+                              map->ptr, map->stride,
+                              map->w, map->h);
+
+   intel_region_unmap(intel, mt->region);
+   free(map->buffer);
+}
+
 /**
  * Mapping function for packed depth/stencil miptrees backed by real separate
  * miptrees for depth and stencil.
@@ -1225,6 +1289,8 @@ intel_miptree_map(struct intel_context *intel,
 
    if (mt->format == MESA_FORMAT_S8) {
       intel_miptree_map_s8(intel, mt, map, level, slice);
+   } else if (mt->wraps_etc1) {
+      intel_miptree_map_etc1(intel, mt, map, level, slice);
    } else if (mt->stencil_mt) {
       intel_miptree_map_depthstencil(intel, mt, map, level, slice);
    } else if (intel->has_llc &&
@@ -1261,6 +1327,8 @@ intel_miptree_unmap(struct intel_context *intel,
 
    if (mt->format == MESA_FORMAT_S8) {
       intel_miptree_unmap_s8(intel, mt, map, level, slice);
+   } else if (mt->wraps_etc1) {
+      intel_miptree_unmap_etc1(intel, mt, map, level, slice);
    } else if (mt->stencil_mt) {
       intel_miptree_unmap_depthstencil(intel, mt, map, level, slice);
    } else if (map->bo) {

src/mesa/drivers/dri/intel/intel_mipmap_tree.h

@@ -190,6 +190,9 @@ struct intel_mipmap_tree
     * MESA_FORMAT_Z32_FLOAT_X24S8, then mt->format will be
     * MESA_FORMAT_Z32_FLOAT, otherwise for MESA_FORMAT_S8_Z24 objects it will be
     * MESA_FORMAT_X8_Z24.
+    *
+    * For ETC1 textures, this is MESA_FORMAT_RGBX8888_REV if the hardware
+    * lacks support for ETC1. See @ref wraps_etc1.
     */
    gl_format format;